Adenosine Mediated Modulation of Cardiac Fibrosis

腺苷介导的心脏纤维化调节

• 批准号: 6895818
• 负责人: Francisco J Villarreal
• 金额: $ 34.2万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-15 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6895818
• 关键词: adenosine; adenosine kinase; angiotensin receptor; cell proliferation; collagen; cyclic AMP; cyclic GMP; echocardiography; extracellular matrix; fibroblasts; fibrogenesis; fibrosis; genetic transcription; green fluorescent proteins; heart cell; heart failure; heart function; kinase inhibitor; laboratory mouse; laboratory rat; myocardial infarction; myocardium disorder; protein biosynthesis; purinergic receptor; scars; tumor necrosis factor alpha

Myocardial fibrosis can contribute to diastolic dysfunction and the development of heart failure. Preliminary results indicate that adenosine (ADO) can inhibit cardiac fibroblast (CF) function. These effects appear mediated via ADO A2b receptors. We will test the hypothesis that: "The enhancement of myocardial adenosine levels reduces the synthesis of cardiac collagens and associated fibrosis through the stimulation of cardiac fibroblast adenosine A2b receptors". We will examine the following aims: AIM 1: Enhanced myocardial ADO levels in the setting of myocardial infarction (MI) inhibits the deposition of cardiac collagens. We will induce the acute deposition of cardiac collagens in rats via MI induced scar formation. To enhance tissue ADO levels we will use the ADO kinase inhibitor compound GP515. We will assess for the functional consequences of the inhibition of scar formation in control untreated and treated MI rats by determining passive and active structure-function and by analysis of the microstructural properties of the scar. AIM 2: Enhanced myocardial ADO levels in the setting of MI reduces in vivo cardiac fibroblast proliferation and type I collagen gene transcription. We will use MI to induce cardiac fibroblast proliferation and collagen deposition in transgenic mice that link the expression of the marker green fluorescent protein (GFP) to collagen type I (CI- GFP) gene expression. Myocardial ADO levels will be enhanced as in aim 1. In vivo CF proliferation, type I gene expression and cardiac function, scarring/remodeling will be assessed at predetermined time points. AIM 3: The absence of A2b receptors in the MI mouse heart impairs the ability of ADO to diminish cardiac collagen synthesis yielding enhanced scar deposition. We will use mice null (-/-) for A2b receptors. We will induce the acute deposition of cardiac collagens in wild type and in A2b receptor null mice by using MI. Tissue ADO levels will be enhanced as in aim 1. Cardiac passive and active structure- function will be assessed at predetermined time points. The effects of enhanced ADO levels will also be examined in vitro using cultured CF from A2b (-/-) mice and assessing for ADO modulation of cell function. AIM 4: ADO inhibits TNF-alpha release and cardiac fibroblast function through the stimulation of A2b receptors and associated increases in cAMP and/or cGMP levels. We will assess for adenosine A2b receptor mediated induced inhibition of CF function and for the role of intracellular cAMP and/or cGMP in mediating ADO induced alterations in CF function.

心肌纤维化可导致舒张期功能障碍和心力衰竭的发展。初步结果表明，腺苷(ADO)对心脏成纤维细胞(CF)功能有抑制作用。这些效应似乎是通过ADO A2B受体介导的。我们将验证这样的假设：“心肌腺苷水平的提高通过刺激心脏成纤维细胞腺苷A2B受体减少了心脏胶原的合成和相关的纤维化”。我们将检查以下目的：目的1：心肌梗死(MI)时升高的心肌ADO水平抑制心脏胶原的沉积。我们将通过MI诱导的瘢痕形成诱导大鼠心脏胶原的急性沉积。为了提高组织ADO水平，我们将使用ADO激酶抑制剂化合物GP515。我们将通过测定被动和主动的结构-功能以及通过分析瘢痕的微观结构特性来评估抑制瘢痕形成在对照组、未治疗和治疗的MI大鼠中的功能后果。目的：心肌梗死时心肌ADO水平升高可抑制在体心脏成纤维细胞增殖和I型胶原基因转录。我们将利用心肌梗死诱导转基因小鼠心脏成纤维细胞增殖和胶原沉积，将标记绿色荧光蛋白(GFP)的表达与I型胶原(CI-GFP)基因表达联系起来。心肌ADO水平将在目标1中得到提高。在体内，将在预定的时间点评估CFs增殖、I型基因表达和心功能、瘢痕形成/重塑。目的3：心肌梗死小鼠心脏中A2B受体的缺失削弱了ADO减少心肌胶原合成的能力，从而增加了瘢痕沉积。我们将使用小鼠的A2B受体为空(-/-)。我们将利用MI在野生型和A2B受体缺失的小鼠中诱导心脏胶原的急性沉积。如目标1所示，组织ADO水平将提高。将在预定的时间点评估心脏被动和主动结构-功能。A2B(-/-)小鼠体外培养的CFs也将检验ADO水平升高的效果，并评估ADO对细胞功能的调节作用。目的4：腺苷通过A2B受体的刺激和cAMP和/或cGMP水平的升高来抑制肿瘤坏死因子-α的释放和心脏成纤维细胞的功能。我们将评估腺苷A2B受体介导的对CF功能的抑制以及细胞内cAMP和/或cGMP在介导ADO诱导的CF功能改变中的作用。